Cardiac problems are a major global health concern. According to the American Heart Association, 1.26 million people suffer from heart attacks annually. If the patient survives, they are at a high risk for developing heart failure. Left ventricular remodeling contributes to heart failure, which in 1995, affected 2 million people (Schocken et al, J Am Coll Cardiol. 1992 Aug.;20(2):301-6). The incidence and death by heart failure has been steadily increasing for years, suggesting that the potential patient population may continue to grow significantly over time. Many therapeutic approaches, both pharmacologic and surgical, have been developed to treat heart failure. Most therapies are directed at patients who have already developed symptoms. Few if any are directed at patients in the early post myocardial infarction time period before symptoms develop. None are directed at limiting extracellular matrix destruction by matrix metalloproteinases. Typically, a patient suffering a heart attack is given a cocktail of medicines that can be difficult to titrate and manage. Efficacy is often not achieved. The population of heart failure patients continues to grow in spite of the current therapeutic armamentarium.
In a paper published in Circulation (June 2003, p 2857), Wilson et al determined that certain matrix metalloproteinases (MMP), such as MMP-13 are upregulated post-MI, perhaps resulting in the left ventricular remodeling that adversely affects heart function. Further, they found that the antagonist to MMP-13, TIMP, is down-regulated. In particular, this study demonstrated increased levels of MMP-13 and MTI-MMP after MI, which may have particular significance with respect to pathological remodeling. Specifically, MMP-13 is increased in end-stage cardiomyopathies and aggressive breast carcinomas. MMP-13 degrades fibrillar collagens and therefore may contribute to myocardial extracellular remodeling. Increased MT1-MMP levels within the transition and MI regions may have particular significance, for two reasons. First, MT1-MMP degrades a wide range of extracellular matrix proteins. Second, MT1-MMP can proteolytically process soluble pro-MMPs, such as pro-MMP-13,2 and thereby amplify local proteolytic activity. The LV regions in which this local induction of MT1-MMP and MMP-13 occurred were paralleled by decreased TIMP levels. The present study demonstrated that increased MT1-MMP levels and decreased TIMP-4 levels were correlated to the extent of regional LV remodeling. This regional imbalance between these specific MMPs and TIMPs probably contributed to continued regional expansion in the post-MI myocardium.
There is a need in the art for treatments to minimize left ventricular remodeling associated with MI. In addition to LV remodeling uses, there is also a need in the art to provide regional delivery of MMP inhibiting therapy that would be active only where MMP's are active.